1. Field of the Invention
The invention relates to the catalytic production of nitriles and primary amines from primary alcohols, and more particularly relates to the production of nitriles and primary amines at lower temperatures over a catalyst containing copper and chromium.
2. Description of Related Methods
The production of primary amines from primary alcohols and ammonia would be a very desirable process if it could be performed with high selectivity to the amines. The reductive amination of secondary alcohols proceeds well, but primary alcohols frequently give undesired by-products including secondary amines and hydrogenolysis products. For example, Japanese Pat. No. 75-30,804 (Chemical Abstracts 83: 58081g) relates that a nickel-copper-chromium catalyst may convert ammonia and 1-butanol at a 93% conversion, to n-butyl amine in only 64% selectivity at a temperature of 205.degree. C. and a pressure of 2,275 psig. The same patent reveals that n-dodecanol may be converted to dodecyl amine in 55% selectivity. High conversions would be necessary in a process such as this because of the proximate boiling points of the primary amine and primary alcohol, and therefore the distillation to remove the unreacted alcohol would be difficult. Further, Japanese Pat. No. 75-32113 (C. A. 83: 78568z) teaches that higher selectivity to the primary amine may be achieved but at the expense of conversion. In that patent, the conversion of dodecanol to dodecyl amine is achieved with 95.3% selectivity, but at a 71.7% alcohol conversion. The reaction therein was conducted at 120.degree. to 220.degree. C. under atmospheric pressure using a cobalt catalyst containing magnesium, calcium, zinc, cadmium and/or manganese.
A titanium oxide/molybdenum oxide catalyst yields decyl amine and 1-decene from 1-decanol in the vapor phase according to Takita, Y.; Seyiama, T. and Nishida, Y., Bull. Chem. Soc. Japan, 49 (12), pp 3699-3700, Dec. 1976. In that article, the highest n-decyl amine selectivity achieved was 68.7% at 11.2% conversion.
French Pat. No. 1,302,365, which corresponds to British Pat. No. 934,636, indicates that a nickel catalyst may promote the formation of primary, secondary and tertiary amines from ethylene glycol monomethyl ether in yields of 35, 40 and 3%, respectively. None of these methods has been able to convert primary alcohols to primary amines with both high conversions and high selectivities.
There has been recent work in the vapor phase reductive amination of primary alkanols with secondary amines to produce the corresponding tertiary alcohols in high selectivity. The catalyst employed was copper chromite supported on silica, and other copper catalysts. See, for example: Baiker, A. and Richarz, W., Helv. Chem. Acta, 61, pp 1169-1174 (1978); Baiker, A. and Richarz, W. Synthetic Comm., 8(1), pp 27-32 (1978); Baiker, A. and Richarz, W., Tet. Lett., 1977, pp 1937-38; also Preprints - Can. Symp. Catal., 5th, 1977, Chem. Inst. Can., Ottawa, Ontario, pp 1169-1174; and finally German Offen. No. 2,535,073 issued on Feb. 17, 1977.
Typically, conversions and selectivities are greater than or equal to 97%.
Nitriles have been formed from amines or by the amination of alcohols over various catalysts, but only at higher temperatures than those used in the inventive method. For example, Migrdichian in The Chemistry of Organic Cyanogen Compounds, ACS Monograph No. 105, Reinhold, New York, 1947, p 168 (see also U.S. Pat. Nos. 2,337,421 and 2,337,422) indicates that alkyl amines are converted to nitriles at 320.degree. to 330.degree. C. over nickel catalysts or at 400.degree. to 420.degree. C. over copper catalysts. Alcohols can be converted to nitriles in the presence of ammonia over "dehydrogenation catalysts" at 300.degree. to 400.degree. C. Another group has reported the same reaction over FeS at 450.degree. C., Zakirov, N. S., Absurakhmanov, E. A., and Kusainov, Kh. Sh., (Sammarkand) Neftekhimiya, 1978, 18 (1), 75-9 (C. A. 88: 169565r).
Other workers have used zinc oxide or magnetite as the catalyst, as shown in Jodra, L. G.; Arogan, J. M. and Corella, J., Acta Cient Compostelana, 14 (1), (1977), pp 85-102 (C.A. 87:133846y).
Japanese investigators have reported mixtures of secondary amine, nitrile and hydrocarbons from the treatment of 1-butyl amine with hydrogen over a cobalt-molybdenum-aluminum oxide catalyst at approximately 200.degree. to 500.degree. C., Hattori, T.; Kanetake, K. and Murakami, Y., Nippon Kaguku Kaishi, 1977 (11), pp 1591-96.
Production of nitriles from alcohols or aldehydes at 470.degree. C. over a zinc oxide on aluminum oxide catalyst has been taught in German Offen. No. 1,816,279, issued on July 16, 1970, and French Pat. Nos. 1,550,144 and 1,562,129.